Short pulse injection seeding of Q-switched Nd:glass laser oscillators-theory and experiment

A 0.5-GW-peak-power solid-state laser source that is based on injection seeding a Q-switched Nd:Glass laser is discussed. In the first experimental demonstration, a Q-switched oscillator producing 101 mJ was seeded by a train of 11-ps pulses from a CW (continuous-wave) mode-locked laser to produce injection-mode-locked pulses under a 91-ns envelope. A theoretical analysis of injection seeding of a high-gain Q-switched oscillator by the output of a mode-locked oscillator is presented. The numerical analysis predicts the minimum signal power required for injection mode locking and the temporal shape of the output pulse. The experimental results agree well with the theoretical predictions. The amplification demonstrated by this technique is 104.4 dB, which is much greater than that demonstrated by a multipass or regenerative amplifier. The experimental advantages of injection mode locking include greater than 100 dB of effective amplification and noncritical cavity length adjustment of the seed resonator